1 - Interfere with a catcher's throw
When a base runner is stealing and the catcher comes up quickly with a throw to attempt to retire the runner, the batter cannot in any way impede the catcher's effort – either intentionally or unintentionally. If he does, then the batter is out, the ball is dead, and all runners must return to their time-of-pitch base.
The most common steal-and-throw scenario is a runner stealing second on a pitch (as opposed to a passed ball or wild pitch). Sometimes you see a steal of third, but not very often. So on a steal of second base, you don't often have interference because the catcher has a clear line of sight to second base.
But sometimes you do – for example, when the batter's swing pulls him off balance and he steps onto or across the plate. If there is a runner stealing second when this happens, you can very easily have batter's interference. When stepping over the plate, the batter can easily bump or otherwise impede that catcher's attempt to throw down to second. That's interference.
Note: If you see batter's interference, but the catcher gets the throw off anyway and succeeds in retiring the runner, then ignore the interference. By Rule 6.03(a)(3), if the catcher retires the runner, then, in effect, the interference never happened. On such a play, then, if other runners were also stealing when the interference is waved off, they get to remain at the base they stole.
We said a moment ago that most of the time the steal is of second base. But not always. Sometimes you get a base runner stealing third, and this is the case where you really need to watch for batter's interference. That's because the throw to third often requires the catcher to throw across the right-handed batter's box. And that's where the batter is standing (if he's right-handed). And you can't expect the batter to simply disappear.
Now, this gets a little bit tricky. There is a common misconception that if a batter remains in the batter's box he cannot be called out for interference. This is not true. The batter's box is not a safe haven. But, as we said, he can't be expected to disappear, either. Add to this that a play on a steal of third happens so friggin' fast that the batter may not even know a play is on until the ball goes whizzing by.
And let's not forget about snap throws down to first base to catch a runner leading off too aggressively, or who may not be paying attention (yep, sometimes they catch runners sleeping). You have the same issue here as you do with throws to third, but instead it's with left-handed batters.
So, with all of this fuzzy grey zone, what's an umpire to do? Well, the wording of 6.03(a)(3) is important here: The batter is out if he "… interferes with the catcher's fielding or throwing by stepping out of the batter's box or making any other movement that hinders the catcher's play at home base." As directives go, you can't get much broader than "any other movement." Batter beware.
The emphasis is important because "any other movement" covers a lot of ground. A lot. So the message is, give the balance of judgment to the catcher. Sometimes a bad throw is just a bad throw and you have nothing. But if the catcher's throw gets disrupted in any way, regardless of intent, you've got to call it.
But again (for the third time), you can't expect the batter to simply disappear. You have to watch and judge for yourself whether the batter made "any other movement" that hindered the catcher in any way. This is a judgment call, of course. Generally (generally), if the batter remains still in the batter's box and makes no movement, then he is protected from interference. If it were me, though, I'd duck. But that's just me.
https://www.umpirebible.com/index.php/rules-batting/batter-s-interference